定时器任务不起作用!
我尝试使用计时器任务刷新用定点坐标绘制的线(每1秒后)。但该行似乎没有刷新...我的代码有什么问题吗?
LineRefresh.java:DrawView.java
package LineRefresh.xyz.com;
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
public class LineRefresh extends Activity {
DrawView drawView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
drawView = new DrawView(this);
drawView.setBackgroundColor(Color.WHITE);
setContentView(drawView);
}
}
:
package LineRefresh.xyz.com;
import java.util.Timer;
import java.util.TimerTask;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.View;
public class DrawView extends View {
Paint paint = new Paint();
public DrawView(Context context) {
super(context);
}
@Override
public void onDraw(final Canvas canvas) {
paint.setColor(Color.BLACK);
canvas.drawLine(50, 200, 270, 200, paint);
Timer timer = new Timer();
TimerTask task = new TimerTask() {
@Override
public void run() {
paint.setColor(Color.BLACK);
canvas.drawLine(50, 200, 270, 200, paint);
}
};
timer.schedule(task, 1000,1000);
}
}
我应该将计时器任务放在代码中的其他位置吗?
i have tried using a timertask to refresh a line(after every 1 second) drawn with fixed point coordinates. But the line doesn't appear to refresh...is there anything wrong in my code?
LineRefresh.java:
package LineRefresh.xyz.com;
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
public class LineRefresh extends Activity {
DrawView drawView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
drawView = new DrawView(this);
drawView.setBackgroundColor(Color.WHITE);
setContentView(drawView);
}
}
DrawView.java:
package LineRefresh.xyz.com;
import java.util.Timer;
import java.util.TimerTask;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.View;
public class DrawView extends View {
Paint paint = new Paint();
public DrawView(Context context) {
super(context);
}
@Override
public void onDraw(final Canvas canvas) {
paint.setColor(Color.BLACK);
canvas.drawLine(50, 200, 270, 200, paint);
Timer timer = new Timer();
TimerTask task = new TimerTask() {
@Override
public void run() {
paint.setColor(Color.BLACK);
canvas.drawLine(50, 200, 270, 200, paint);
}
};
timer.schedule(task, 1000,1000);
}
}
sholud i,instead, place the timertask somewhere else in my code?
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而是使用 Android Handler 在一定时间后更新 UI。
Rather use Android Handler to update UI after certain time.